Process of manufacturing alkali silicates.



UNITED STATES" PATENT OFFICE,

FRANK P. VAN DENBERGI-I, OF BUFFALO, NEW YORK.

PROCESS OF MANUFACTURING ALKALl SILICATES.

SPECIFICATION forming part of Letters Patent No. 677,906, dated July 9, 1901.

Application filed August 3, 1900. Serial No. 25,821. (No specimens.)

To all whom it may concern.-

Be it known that I, FRANK P. VAN DEN- BERGH, a citizen of the United States, residing at Buffalo, in the State of New York, have invented certain new and useful Improvements in Processes of Manufacturing Alkali- Metal Silicates; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable those skilled in the art to which it appertains to employ the same.

More particularly, my invention relates to a new and improved art or process for the production of alkali-metal silicates from sodium chlorid or potassium chlorid or other materials containing sodium or potassium or their salts and a silicious substance or substances by means of heat and electrolysis, one or both being produced by an electric current in the presence of an oxidizing agent or agents.

In carrying out my inventionl use sodium chlorid or potassium chlorid or other suitable materials containing sodium or potassium or their salts and a suitable silicious substance-such as silica, sand, silex, quartz, cullet, feldspar, or other suitable materialand these are reduced to a molten mass within the furnace-chamber by the heat of the electric current, either with or without the auxiliary heat of internal or external combustion. This fusion of the materials is caused to take place in an atmosphere which contains an excess of oxygen, which is supplied by any suitable meanssuch as iron oxid, manganese oxid, the sulfate, nitrate, or other oxygemyielding salt of sodium or potassium, or other suitable solid which may be mixed with the materials fedinto the furnace, or by water, steam, air, oxygen, ozone, or other suitable oxygen-yielding liquid or gas which may be injected into the furnace, so that the decompositions and reactions which take place in the molten bath or within the furnace-chamber and the products resulting therefrom take place and are in the presence of an excessive supply of free oxygen or oxygen which is in the nascent state. The principal purpose of such oxidation is to avert the formation of sodium or potassium silicid or of certain silicates of incomplete oxidation-that is, containing a less relative proportion of oxygen--and to insure the formation of the normal or ortho silicates of sodium or potassium. This bath or molten mass is subject to intense heat and to electrolysis, one or both due to the electric current, the heat principally serving to reduce the materials to a fluid condition and the electrolysis serving principally to effect decomposition of the materials.

The sodium or potassium salts and the sili cious material being together introduced into the furnace, the first effect is to fuse these materials. Subsequently the salts under the influence of the electric currentare decomposed, and the resulting gas or gases, as chlorin, in the case of sodium or potassium chlorid, are liberated and conducted away through a suitable conduit leading from the furnace and utilized by any of the methods in use for the manufacture of hydrochloric acid, liquid chlorin, bleaching-powder, hypochlorite solutions, or other products of value in the arts.

The principal reaction which takes place and that which is essential to carrying out my process may be expressed by the following empirical formula:

4NaCl+SiO +O :SiO Na +2Gl that is to say, common salt and silica re-= acting on each other in the presence of oxygen under the conditions hereinbefore expressed result in the production of normal or ortho sodium silicate and free chlorin.

. In preparing the mixture to be fed into the furnace the composition of the materials is to be observed with care, and they are to be added in such proportions and with such admixtures of auxiliary electrolytes or fluxes as to secure and maintain fusion at the lowest temperature and to secure and maintain decomposition by electrolysis with the greatest economy as to materials, time, and current. For instance, when operating with sodium chlorid a small proportion of a potas sium salt will result in a lowering of the fusing-point of the bath and will at the same time facilitate electrolysis.

It is desirable that the resulting silicate should be as fluid as possible, as well after it issues from the furnace as when molten therein, and to this end care must be exercised as to the proportions of the materials used.

alkali-metal base and the silicious material;

are first broken or crushed to such a condition as to permit and facilitate feeding them into an electric furnace and also to facilitate their fusion. The electric furnace employed may,be of any desired type, provided it has a properly-closed chamber and a proper exit for the vapors generated connected with a condensing apparatus.

It is especially advantageous, however, to employ a furnace affording a continuous process of reduction that is, of fusion and decomposition-and a furnace well adapted for this purpose has heretofore been designed by me and upon. which Letters Patent were issued to me u'nder date of July 4:, 1899, and bearing number 626,373.

The material to be treated is introduced into the furnace and brought into contact with the electric current and is rapidly converted into a molten mass. silicio'us material which is used cannot be The exact amount-of stated arbitrarily owing to the variations in the character and richness of the materials I which maybe used and must be in eachcas'e relativelydetermined, as it may be by any person skilled in the art of smelting ores. 5% Likewise the volume and-quantity of the elec- E tric current employed, as he'reinbe'f'ore' set; forth, for the purposes of heat andelectrolysis will be determined by'the work being done and "the character of the materials being treated.

For the com plete and certain oxidation-and hydration of the moltenmass it is usually desi'rable to project a jet of steamer air directly 3 into the furnace, and its quantity must also; be determined by the quality of the native n1 a'terialsbeing operated u pon'an'd their qnantity. I However, the material'used in carrying out my process is such and its physical coilanion, being broken into small pieces, is such L that large volumes of air are necessarily 'de- 1 livered into the furnace-chamber along with the material.

The materials used also carry with them a considerable-and-often very large I amounts of water, so that it is -not always necessary to introduce the steam into the furl Vhe'ther or not this is necessary has made.

to be determined by the condition of the ma-* terials being operated upon.

The'molten silicate or mixture of silicates in the condition of soluble glass is caused to flow away from the furnace into a proper receptacle, vat, or 'tank containing water,

wherein it may be further treated in such manner as may be desired-as, for instance, by the passage of carbon dioxid through the liquid, thus decomposing the fluid silicate with the formation of carbonate of sodium and the liberation of silica as hydrated silica, or by the addition of milk of lime causing the decomposition of the alkali-metalsilicate with the formation of silicate of calcium and the liberation of the alkali as caustic soda or caustic potash. I do not, however, restrict or limit my invention to the particular means described for carrying out the process, as any one and all of them may be varied without departing from the spirit of my invention, and I do not limit myself to the use of steam or water-vapor as an oxidizing agent, as oxygen or air, ozone, hematite iron ore, or other suitable material capable of yielding a large proportion of oxygen when subjected to the heat and energy of the electric current within the furnace may be employed, and these oxygen-yielding materials may be heated separately from the sodi um or potassium yielding materials, as is sometimes desirable.

Having thus described my invention, what 5 I claim, and desire to secure by Letters Pat out, is-

1. The herein-described process or manufacturing alkali-metal silicates, which consists in subjecting a substance containing an alkali-metal base, anda silicious-su bstance in the presence of oxygen, to heat and electr'oly sis, "to fuse the mass and drive off the 'acidre lous elements "or oxids, and-combine the base and silicate form an alkali-metal silieate,-substa'ntially as set forth.

'2. I The herein-described process, of manufacturing alkali-metal silicates, which consists in subjecting an alkali-metal chlorid and a s'il'icious substance to heat sufficient tofuse the-same, and to electrolysis to drive off the chlorin and permit the combination of the alkali-metal base with the fused "silica in the presence of oxygen, substantially asset forth.

3. The herein-described process of manufacturing alkali-metal silicates, which consists in subjecting an alkali-metal chlorid and a silici'ous substance, in the proportion of appr'oximatelythree parts'of chlorid to one of the silicious substance,to heat "and electrolysis 'in the presence of oxygen, substantially as set forth. 7

i. The herein d-escribed process of manu facturing alkali-metal silicates, which consists in subjecting sodium chlorid and a smaller proportion of potassium chlorid, and a substance containing silica, to heat and electrolysis in the presence of oxygen,'the potassium chlorid serving to lower the fusingpoint of the bath, and also to facilitate the electrolysis, substantially as set forth.

5. ilheh-erein-described process of manufacturing alkali-metal silicates containing a high proportion of oxygen, which consists in subjecting asubstance containing an alkalimetal base, auda silicious substance to heat and to electrolysis, ample to fuse the mate- 'rial'sand drive off th'e'acidulous constituents,

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substantially as set forth.

7. The herein-described process which consists in subjecting to heat and electrolysis in the presence of oxygen an alkali-metal chlorid, and a silicious substance to form an alkali-metal silicate, and then treating the silicate so formed to produce a caustic alkali, substantially as set forth.

FRANK P. VAN DENBERGI-I.

Witnesses:

GEO. J. MAY, Jr., LEWIS I. ONEAL; 

